Improvement Method of Voltage Sharing Performance for Series-Connected GaN Devices based on an Active Surge Absorber Circuit

This study discusses series-connected gallium nitride (GaN) devices with active surge absorbers (ASAs). To respond to high-speed switching of GaN devices, we propose a circuit scheme using passive elements with a simple structure. The proposed circuit scheme improves the voltage sharing ratio of GaN devices in series, and realizes high breakdown voltage and low loss by series-connected GaN devices. In this study, the theoretical improvement of the proposed circuit scheme was derived and tested by simulation. As a result, it was confirmed that the unbalance of the voltage sharing ratio can be improved by 87.5% compared to the case without the ASAs circuit.